A-Gear: A flexible exoskeleton that helps patients with muscle degeneration retain the use of their arms

Duchenne Muscular Dystrophy (DMD) is a serious neuromuscular disease, affecting approximately 1 in 3,600 boys, which often results in severe muscle degeneration and in some cases, premature death. Caused by mutation of a specific X-linked gene, the disorder is usually associated with progressive muscle weakness and even loss of muscle mass, gradually leading to a point where the sufferer entirely loses the ability to use his arms and legs. To assist DMD patients in their daily activities, a team of Dutch scientists has developed A-Gear, a highly flexible robotic arm that can be worn underneath clothing.

Designed by experts from Netherlands-based MIRA Research Center, in collaboration with Delft University of Technology, VU University Medical Center and Radboud University Nijmegen Medical Center, this intuitive body-connected exoskeleton is intended to help people with Duchenne disease retain the use of their arms, especially while performing simple, daily tasks. Unlike similar support aids currently available for DMD victims, the new technology strives to restore complete muscle function, in a discreet, stigma-free manner.

To build the exoskeleton, the researchers referred to the Duchenne Dynamic Arm Study (DDAS), in order to conduct a thorough analysis of the muscular changes taking place during the entire course of the disease. The result of four long years of research, A-Gear comes in two different designs: a passive arm support suitable for use by those who can control their arm movements on their own, no matter how slightly. Driven mechanically without the help of any motor or power source, this highly-specialized exoskeleton helps enhance the user’s muscle strength and agility to a great extent.

Developed primarily for patients with severe, irreversible muscle degeneration, the other model features an active arm support, powered electrically by means of motors. To ensure that the user’s movements are natural and intuitive, the system works on electrical muscle signals, produced as a result of minute arm movements, such as twitching. Speaking about the research, Joan Lobo-Prat, a scientist at the MIRA center, said:

During the research, there were a number of participants who had been unable to independently move their arms for between three and five years and they were able to complete the tests set out in the tasks. The freedom of movement and the functionality of the arm increased when the subjects used the prototype. In addition, the movements required less energy.

In laboratory tests, patients, who had previously lost the ability to move their arms for around three to five years, were able to perform a series of tasks involving their upper limbs. At present, the team is trying to convert the prototype into a lightweight and efficient product that is easy to manufacture as well as use.